1. Technical Field
The present invention relates to allocation of resources to femto cell base stations and relay stations and, more particularly, to allocation of time-frequency blocks of orthogonal frequency division multiple access (OFDMA) frames to femto cell base stations and relay stations.
2. Description of the Related Art
Femto cells are a cost-effective means of providing ubiquitous connectivity in future broadband wireless networks. In general, femto cells have primarily been used to improve coverage in current business solutions. There has been a significant impetus towards the deployment of these femto cell solutions by several cellular providers, which has also increased their importance for consideration in the future OFDMA-based standards such as Long Term Evolution (LTE) and for use in technologies such as World Interoperability for Microwave Access (WiMAX).
Current UMTS-based femto solutions have focused on improving indoor coverage in existing cellular systems. Here, users that are moved to femto cells experience increased throughput due to shorter ranges. In turn, users communicate to the macro cell base station via the femto cells by using a cable backhaul between femto cells and the macro cell base station. UMTS-based femto cell solutions are similar to other femto cell solutions in that they are driven primarily from a business incentive perspective, where the ability to reuse cable backhaul helps provide extended coverage to users, thereby reducing user-churn for network providers. Hence, current UMTS-based femto solutions mainly focus only on interference mitigation between macro and femto cells through way of power control.
An architecture that is analogous to some degree to femto cell systems currently used is that of wireless local area network (WLAN) hotspots inside a macro cell. Several works have examined problems pertaining to handoff, coverage, etc. in the combined wireless wide area network (WWAN)-WLAN architecture. However, the varied technologies and spectrums employed decouple the resource management problem in the two separate networks using two different sets of resources. The WLAN hotspot technologies do not consider managing shared, common resources between different types of networks.
With regard to distributed channel allocation schemes, WLAN technologies only focus on access points converging to a single mutually orthogonal channel for operation, after which the allocation can be statically retained. Medium access control (MAC) in ad-hoc networks offer another means for resource allocation in distributed operations. However, they are typically variants of 802.11 MAC protocol that use control messages in aiding the distributed control.